Methods to create and parse ISO date strings without NSDateFormatter.

NSDate ISO methods

NSDate *CBCBDateFromISOString(NSString *iso)
{
    struct tm tm;
    time_t t;
    
    if (iso.length == 10) {
        
        strptime([iso cStringUsingEncoding:NSUTF8StringEncoding], "%Y-%m-%d", &tm);
        tm.tm_isdst = -1;
        tm.tm_sec = 0;
        tm.tm_min = 0;
        tm.tm_hour = 0;
        t = mktime(&tm);
        
    } else {
        
        strptime([iso cStringUsingEncoding:NSUTF8StringEncoding], "%Y-%m-%dT%H:%M:%S%z", &tm);
        tm.tm_isdst = -1;
        t = mktime(&tm);
        
    }
    
    return [NSDate dateWithTimeIntervalSince1970:t + [[NSTimeZone localTimeZone] secondsFromGMT]];
}

NSString *CBCBISOStringFromDate(NSDate *date)
{
    struct tm *timeinfo;
    char buffer[80];
    
    time_t rawtime = [date timeIntervalSince1970] - [[NSTimeZone localTimeZone] secondsFromGMT];
    timeinfo = localtime(&rawtime);
    
    strftime(buffer, 80, "%Y-%m-%dT%H:%M:%SZ", timeinfo);
    
    return [NSString stringWithCString:buffer encoding:NSUTF8StringEncoding];
}